The influence of differing protected area status and environmental factors on the macroinvertebrate fauna of temperate austral wetlands

Abstract

One means of conserving wetlands is to designate the area around them as 'protected'. Although many different types of protected areas exist, ranging from international (Ramsar-listed) to local importance, there is little information on how the type of protection influences biodiversity conservation. Studies of the effectiveness of protected area systems are a priority, if we are to understand their importance and design systems effectively. Many Tasmanian wetlands are regarded as having high to very high conservation values with more than 60% located within protected areas. This study tested macroinvertebrate richness and assemblage responses to a range of environmental attributes and differing types of protected area status at 66 protected Tasmanian (Australian) wetlands. Two hundred and eighteen taxa were identified with an average of 33 species (or morphospecies) and 18 families recorded per wetland. The wetland assemblages were idiosyncratic, four families contributed 21% of the total recorded and only two families contributed greater than 10%. Wetlands were not significantly nested on the basis of the composition of their macroinvertebrate assemblages. No single environmental attribute had a strong relationship with macroinvertebrate richness or assemblage composition and neither species richness nor assemblage composition varied significantly between different types of protected areas. Although the majority of protected area types were designed to support terrestrial conservation objectives rather than wetland values, our results suggest that the latter were also afforded protection. The state of the proximal zone (the terrestrial zone within 50m of the wetland edge) and the type of aquatic habitat present (macrophyte or sediment-dominated substrates) were the most important determinants of macroinvertebrate richness and assemblage composition across all types of protected wetlands. These results suggest that for temperate austral wetlands located within protected areas, the macroinvertebrate fauna will be best conserved by minimal disturbance of proximal lands.